The dramatic curse of the second part struck A Passionate Woman (BBC1)with what can only be described as stunning force. At least Sue Johnston appeared dazed and confused, but then wouldn't anyone with a pair of tennis balls lodged in their cheeks. What they were doing there was never explained – perhaps she had opened her mouth too wide while passing a public court – but whoever was responsible for them most surely double-faulted.

We left the first part in 1959 with Billie Piper mourning the death of her Polish lover, murdered by his betrayed Geordie wife. It all seemed like a nicely observed period tale of thwarted romance, loveless marriages, and desperate dance halls. There was, it's true, a steady drip of kitchen sink cliches but Piper managed to bring something fresh and authentic to a slightly mouldy scenario, despite having to contend with a performance from Theo James as her dreamboat that was only faintly more convincing than Gordon Brown's smile.

The second part took place just over 25 years later, towards the end of the 1984-5 miners' strike. And something quite strange had taken place, more in keeping with science fiction than a romantic drama: Piper's character had aged at double the rate of the rest of the human race, and in particular of her sister.

Going on the clues from the first part, Piper's character probably would have been around 50, and perhaps even younger, by 1985. But she was played in the second part by Johnston who is 66 and acted as if she had already advanced into septuagenarian senility. It's possible, I suppose, that the engorged cheeks were intended to lend Johnston a more youthful appearance. And in a way they did. She looked like a spry chipmunk between the eyes and mouth, but that only made the rest of her seem even more like a demented granny.

Meanwhile, Johnston's sister in the film, who had been close in age in the first part, was played by Frances Barber in the second, who is 51 and acted as if she was 15. Such was the distracting, not to say disorienting, effect of these age discrepancies that it was a struggle to concentrate on the plot.

To be fair to the plot, though, it didn't encourage concentration. On the announcement that Johnston's son was about to emigrate to Australia with his new wife, the story lamely hinged. Because that's what unhinged Johnston, which, given the tennis balls, was never going to take a lot of doing.

Thereafter, each scene grew progressively longer and denuded of purpose, like a recurring argument that nobody wanted to have but which nobody knew how to end. One felt sorry for Alun Armstrong, a fine actor with a face like a wet day in Grimsby. He had to keep saying "Come on, love" and other dull encouragements, but there was no coming or going. The story was stuck, a position that was symbolised by Johnston's sitting on top of a roof, while the rest of cast took turns overacting.

In the absence of a resolution, there was a tacked-on happy ending in which Johnston and Armstrong forgot their three decades of joint misery and went off together in a balloon. Perhaps the message was that romantic love is a lot of hot air. But after watching three hours of a zombie marriage, that seemed, even more than Johnston's new face, like an awful lot of cheek.

Louis Theroux has an expression, a sort of anxious glare, that has served him well over the years. It says he's with the viewer but he doesn't want to abandon his subject. He doesn't want them to look weird or foolish, but at the same time he wants us to know that the thought has crossed his mind. He usually wears it when he's standing stiff and motionless and somebody has said something that is a cause for concern. At such moments he looks like a man with an upset stomach who is far from confident about the outcome.

We saw that expression several times during Louis Theroux: America's Medicated Kids (BBC2), usually when one of the children were behaving badly in front of their parents. The premise was not full of promise. I think we all understand by now that America contains some strange people who do some strange things and that many of them are not afraid to share their idiosyncrasies with a TV crew. And it's lucky that there are because otherwise Theroux and his various imitators – hello, Mark Dolan – would be out of a job.

In this case, however, there was a proper issue to air and the participants were less eccentric than I feared, and perhaps the film-makers hoped. The children, in particular, seemed relatively normal, but that may be because they were all walking pharmaceutical dumps.

Hugh, a bright 10-year-old living in the Pittsburgh suburbs, was taking Atarol to control attention deficit hyperactivity disorder (ADHD), Tenex to control his impulses (nobody explained what impulses), and Seroquel, an anti-psychotic for bipolar disorder, a diagnosis that in relation to children remains highly controversial.

Theroux asked one of the psychiatrists handing out these drugs at what point the behaviour they were meant to inhibit was deemed pathological. The psychiatrist explained that it was when the children became so annoying they were unable to function. Theroux nodded and said: "Some people think I'm annoying," though you could tell that he found this hard to accept, even if the shrink seemed ready to believe him.

In the end, what undermined the film – not as entertainment, because Theroux does have talent and an oddly appealing charm, but as an experiment – was that, apart from one brief and half-hearted scene with a teenage girl, we didn't see what the children were like without drugs. The suspicion was that pharmacology was standing in for basic parenting, but that's not how the parents saw it. "When she's on medication," said one mother, "she's my best friend." And off medication, she's presumably just her daughter.

The Ricky Gervais Show (C4), which is produced by HBO, is an animated version of the radio show and highly successful podcast by Gervais, Stephen Merchant and Karl Pilkington. The format involves Gervais and Merchant making fun of "the little round-headed buffoon", as Gervais calls Pilkington, whose homespun wisdom is a morose combination of the absurd and the mundane.

Gervais's cartoon looks like Fred Flintstone with a hint of Oliver Hardy, and the lack of resemblance makes you wonder why they didn't just film the three men. For one thing, it wouldn't have been any less funny. The strength of the audio show's comedy lay in its flights of fancy, with which the audience were at imaginative liberty to amuse themselves. But now the surreal jokes are pinned down, and therefore restricted, by cartoon illustrations.

The result looks like the kind of thing at which a student might laugh after holding in marijuana smoke for a long time. You'd have to get mighty stoned, though, to giggle and howl as much as Gervais. It used to be a great comic effect, that laugh, but it's beginning to get a little irritating, like the sound emitted by someone happily going all the way to the bank.

Scene of the week

The second
Leaders' Debate, screened on Sky News, was the revenge of what Nick Clegg likes to call the "old politics". Having gone overnight from Vince Cable's ventriloquist dummy to saviour of the universe, the Cleggster – chief dude of the new politics – received the campaign equivalent of a duffing up behind the bike shed at the hands of the two head prefects.

He knew it was coming, of course, and had probably been fretting about it all the way through double maths, but he still looked as though someone had stolen his lunch money when it arrived. He'd been outlining his plan to replace the Trident nuclear missile system with a global rendition of "Kumbaya", when suddenly that big bully Brown launched his own tactical strike weapon.

"I have to deal with these decisions every day," said Brown, managing, momentarily, to keep the gormless grin away from his mouth, "and I say to you, Nick, get real. Get real."

In its structure and condescension, it was reminiscent of the "I knew Jack Kennedy… Senator, you're no Jack Kennedy" put down with which Lloyd Bentsen famously biffed Dan Quayle. Clegg compounded the effect by replying: "You say 'Get real'", which then allowed Brown to interrupt with another "Get real", and a lecture on the threat from North Korea.

That was three "Get reals", four including his own self-inflicted one, before that cad Cameron slipped one in the solar plexus: "I thought I'd never utter these words, but I agree with Gordon." Ouch!